Systematic assessment of a maxilla of Homo from Hadar, Ethiopia

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132 Citations (Scopus)

Abstract

The Hadar site in Ethiopia is a prolific source of hominid fossils attributed to the species Australopithecus afarensis, which spans the period 3.4-3.0 million years (myr) in the Sidi Hakoma, Denen Dora and lower Kada Hadar Members of the Hadar Formation. Since 1992 a major focus of field work conducted at Hadar has centered on sediments younger than 3.0 myr, comprising the bulk of the Kada Hadar Member. Witnessing the rise of the 'robust' Australopithecus clade(s), the origin of Homo, and the first record of lithic artifacts, the period between 3.0 and 2.0 myr is strategically vital for paleoanthropology. However, in eastern Africa it is a particularly poorly sampled temporal interval. This paper provides a detailed comparative description of a hominid maxilla with partial dentition found at Hadar in 1994. The specimen, A.L. 666-1, derives from a lithic artifact-bearing horizon high in the Kada Hadar Member, 0.8 m below the BKT-3 tephra, dated by the 40Ar/39Ar method to 2.33 ± 0.07 myr. Our preliminary investigation of the hominid specimen showed unambiguous affinities with early representatives of the Homo clade (Kimbel et al. [1996]J. Hum. Evol. 31:549- 561). Further studies on maxillary and dental morphology lead us to attribute A.L. 666-1 to Homo aff. H. habilis. The new Hadar jaw is the first paleontological evidence for the projection of the H. habilis maxillofacial morphotype well back into the Pliocene. It may represent a male of this species, whose maxillary hypodigm consists chiefly of females. A subsidiary finding of our study is that of the three earliest recorded species of Homo (H. habilis, H. rudolfensis, H. erectus), it is H. habilis that exhibits facial morphology closest to that expected in their last common ancestor.

Original languageEnglish (US)
Pages (from-to)235-262
Number of pages28
JournalAmerican Journal of Physical Anthropology
Volume103
Issue number2
DOIs
StatePublished - Jun 1997

Fingerprint

Ethiopia
Hominidae
Maxilla
Homo
artifact
Ephrin-A5
teeth
tephra
projection
Artifacts
Eastern Africa
jaws
ancestry
fossils
Dentition
Fossils
sediments
evidence
Jaw
Tooth

Keywords

  • Dentition
  • Palatefacial morphology
  • Pliocene hominids

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Anthropology

Cite this

Systematic assessment of a maxilla of Homo from Hadar, Ethiopia. / Kimbel, William; Johanson, Donald; Rak, Yoel.

In: American Journal of Physical Anthropology, Vol. 103, No. 2, 06.1997, p. 235-262.

Research output: Contribution to journalArticle

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